MYSTIC, Conn. (CBSNewYork/AP) — A 50-pound vinyl peace sign was stolen from a Mystic playground built in memory of one of the 20 children killed in the Sandy Hook school massacre.

The sign at the entrance to the Grace McDonnell playground was taken Tuesday.

William Lavin, who’s “Where Angels Play Foundation,” has been building playgrounds to honor all 26 victims, told The Day of New London McDonnell’s mother Lynn found out about the theft when the man who apparently took the sign called her.

The thief reportedly told McDonnell he stole the sign because he believes the shooting at the school was a hoax.

McDonnell was upset, and worried about how the theft might affect those who helped build the playground, Lavin said.

The foundation has ordered a replacement sign.

The incident comes less than a week after graffiti was found on another victim’s memorial playground.

The message found spray-painted Sunday at the Ana Marquez Greene Memorial playground in Hartford read, “Peace to Sandy Hook,” using a peace sign and the numeral “2.” It was later removed.

Ana’s mother, Nelba Marquez Greene, told WTNH-TV she was not upset with the graffiti and plans to raise money to put up a graffiti board to allow others to leave similar condolence messages.